Many of my ESL or EFL students are very hard on themselves. They get upset that their English isn't perfect. So while I am happy to teach them the difference between /p/ and /b/ and point out that they aren't using articles (a, an, the) or help them learn new vocabulary words, I think one of the most important things I can teach them is to not stress out about speaking English perfectly. Because even native English speakers make mistakes ALL THE TIME! But the difference is, we don't take it personally.
When I was mispronouncing the word quinoa as [qua-no-ah] my neighbor corrected me, and now I say it correctly, [keen-wah]. I was sure that pilates was pronounced [pie-lates] until an instructor told me it was [pi-lah-teez]. I read a lot, so I come across new words all the time. I just look them up in the dictionary, learn the pronunciation and meaning and move on.
Sometimes I can't even understand other native English speakers. They may talk too fast, or mumble, or turn their head as they are talking. Sometimes I can't even understand my husband, because he is too quiet or doesn't clearly speak his words. These are all common issues, and none of them should be taken personally.
So with my students, I share my own experiences (mistakes?), and teach them coping skills. And I try very hard to teach them to let go of the stress of wanting to be perfect, to instead focus on how far they have already come, but it doesn't always work.
So, I guess I will just keep telling them about all the mistakes I make, because laughing together is always a lot of fun.